1. Field of the Invention
The present invention generally relates to drilling boreholes and, particularly, to identifying breakouts therein.
2. Description of the Related Art
Boreholes are drilled into the earth for many applications such as hydrocarbon production, geothermal production and carbon dioxide sequestration. A borehole is drilled with a drill bit or cutting tool disposed at the distal end of a drill string. A drilling rig turns the drill string and the drill bit to cut through formation rock and, thus, drill the borehole.
Ideally, the drilled borehole is somewhat smooth without interruptions that could cause borehole instability and impede further drilling. Lack of borehole stability can result in reduction in the quality of well log records and, consequently, difficulties in interpreting them. In addition, lack of borehole stability can cause mechanical problems such as stuck pipes, high torque and back-reaming, initiating further problems when setting the casing and removing cuttings. Unfortunately, the drilling process can re-distribute stresses in the formation around the borehole resulting in borehole instability, which can lead to parts of a borehole wall to breaking out of the formation and causing indentations in the borehole wall. This condition is referred to as a “breakout.” It would be well received in the drilling art if drilling operators and site engineers could be alerted to the occurrence of breakouts during the drilling process in order to prevent further drilling and completion problems.